Improvement in processes for sharpening tiles



UNITED STATES PATENT OFFIoE.

MILO A. RICHARDSON, OF BRIDGEPOBT, CONNECTICUT.

IMPROVEMENT IN PROCESSES FOR SHARPENINGTILES.

' Specification forming part of Letters Patent No. 199,573, dated January 22, 1878; application filed October 12, 1877.

Linafter more fully set forth.

In the ordinary use of a file the resistance of the metal upon which it operates tends to wear away the points of the teeth, and there- .by unfit said file for use.

Heretofore files in this condition have either been discarded as worn out, or renovated by tedious, toilsome, and insutficient methods.

I substitute for these methods the use of the well-known sand-blastof a stream of sand driven by steam or air, heated or not' which I direct against the backof the teeth at an angle of from five to ten degrees away from the handle end of the file that is to be sharpened.-

The result of this application is, that the stream of sand impinging upon the file-teeth rapidly wears them away at the back, thus speedily resharpenin g said teeth.

This method or process is applicable to files of any kind or construction.

What I claim is The method of resharpening files by directing upon them a sand-blast, operating to wear or grind away the back of the teeth, and to repoint the same, substantially as set forth.

In testimony that I claim the above I have hereunto subscribed iny name in the presence of two witnesses.

MILO A. RICHARDSON.

Witnesses GEO. W. Lnwrs, HENRY B. BARTRAM. 

